Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Gene Variants May Help Fend Off HIV Infection


A team of researchers based partly in South Africa has identified a key set of immune system molecules that helps determine how effectively a person resists infection with human immunodeficiency virus (HIV). Their work shows that mothers with a specific type of genetic makeup may be less likely to pass HIV to their offspring.

The finding has important implications for the development of vaccines to combat the AIDS epidemic, according to Bruce D. Walker, a Howard Hughes Medical Institute researcher. Walker is one of the leaders of the project, and a professor of medicine at Harvard Medical School and director of the Partners AIDS Research Center at Massachusetts General Hospital.

The research also offers an intriguing glimpse into the simultaneous evolution of a pathogen and its human host. “This is the closest we have come to being able to watch as the evolution of the human population is affected by a pathogen,” Walker said.

The other leaders of the project were Philip Goulder, assistant professor of medicine at Partners AIDS Research Center, and Hoosen (Jerry) Coovadia, professor of HIV/AIDS research at the Nelson R. Mandela School of Medicine at the University of KwaZulu-Natal. A paper describing their work was published in the December 9, 2004, issue of Nature.

AIDS researchers long have wondered why people have varying responses to HIV infection. “Some people rapidly progress to illness within a year or two, while others after 20 years of follow-up are still doing fine,” said Walker. “The range of outcomes is widespread.”

To examine the question, Walker and his colleagues focused on the class I human leukocyte antigen (HLA) molecules that occur in most of the cells in the body. When a cell is infected with a virus, the HLA molecules grab pieces of the proteins made by the virus and display the protein fragments on their surface. Other immune system cells recognize the foreign proteins presented by the HLA molecules and kill the infected cell, thereby stemming the infection.

The research team found that an individual’s response to HIV infection depends heavily on the varieties — or alleles — of the genes encoding HLA molecules that the person has. But not all categories of HLA genes are equally important. The class I HLA alleles are divided into three categories — HLA-A, HLA-B, and HLA-C. Specific HLA-B alleles generate much stronger immune responses than do other HLA alleles. For example, in a study of 706 infected individuals in South Africa who had not yet begun treatment, the type of HLA-B alleles a person has affected the amount of virus in the blood; the number of CD4 cells a person has (a common measure of immune system health); and immune reaction to proteins made by HIV. By contrast, different alleles of HLA-A and HLA-C genes had no effect on the immune response.

“The B alleles are doing most of the work,” said Walker. Vaccine developers therefore should give close attention to responses generated by the HLA-B alleles, “since those seem to be the critical ones that influence viral load.”

The involvement of the HLA-B alleles was particularly interesting to the researchers, since HLA-B alleles are much more diverse than either HLA-A or HLA-C alleles in human populations. Immunologists often have speculated that the greater diversity of HLA-B alleles indicates that they have been important during human history in fending off attacks from other pathogens. For instance, evolutionary forces may have promoted the diversification of HLA-B alleles so that human populations would present a multifaceted defense against infection.

In their Nature paper, Walker and his colleagues point out that the evolutionary influence of the HIV epidemic on HLA-B alleles already can be seen in the offspring of mothers infected with HIV. Mothers with protective alleles pass on HIV infection to their children less often than do mothers with alleles that do less to stop the progression of the disease. As a result, the frequency of the protective alleles would be expected to grow in the population.

The researchers conducted much of their work at the new Doris Duke Medical Research Institute in Durban, which is the largest city of KwaZulu-Natal Province in South Africa. The province is at the epicenter of the HIV epidemic in sub-Saharan Africa. In KwaZulu-Natal Province, a third of pregnant women are infected with HIV, and in Durban, prevalence among pregnant women exceeds 50 percent.

Doing AIDS research in South Africa “is one of the things we’re most excited about,” said Walker. Based on previous research experiences in the country, Walker and several colleagues associated with Harvard Medical School and Massachusetts General Hospital knew that South Africa had very talented scientists. But they were also aware that those researchers did not usually have the financial support to develop professionally.

“We decided to set our sights high,” Walker said. “We decided to build the world’s best biomedical research institute and put it right in the middle of the world’s worst HIV epidemic, because we knew that that would facilitate the science needed to understand why the epidemic is so bad there, as well as vaccine development.”

Funding from the Doris Duke Charitable Foundation through Massachusetts General Hospital enabled construction of the institute at the University of KwaZulu-Natal’s Nelson R. Mandela School of Medicine. “The institute opened its doors in July 2003, and in December 2004 we have a Nature paper by a first-author, who is South African and who was not doing research when we arrived because of a lack of opportunities,” said Walker.

Photini Kiepiela, the first author of the article and a researcher at institute, agreed that the establishment of the institute was critical in generating the new results. “The purpose of doing this work here is to nurture local South African scientists. [And] if not for this institute, it would not have been possible to do this work here.”

Jim Keeley | EurekAlert!
Further information:

More articles from Health and Medicine:

nachricht Inflammation Triggers Unsustainable Immune Response to Chronic Viral Infection
24.10.2016 | Universität Basel

nachricht Resolving the mystery of preeclampsia
21.10.2016 | Universitätsklinikum Magdeburg

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

The nanostructured cloak of invisibility

25.10.2016 | Life Sciences

Oasis of life in the ice-covered central Arctic

24.10.2016 | Earth Sciences

‘Farming’ bacteria to boost growth in the oceans

24.10.2016 | Life Sciences

More VideoLinks >>>